Typically belt conveyors for granular material such as grain, oilseeds, fertilizer, and like agricultural products typically comprise an upper run of the belt passing through a tube that supports the belt in a troughed configuration. The tube is mounted on a mobile framework in an inclined orientation. The belt passes over a top roller at the upper discharge end of the conveyor, and the return run of the belt runs under the tube in a flat orientation supported by idler rollers, plate sections or the like spaced at suitable intervals under the conveyor.
The return run typically passes through an S-drive mounted under the conveyor tube. In the S-drive, idler rollers cause the belt to wrap around the drive roller, increasing the frictional force between the belt and drive roller and allowing significant power to be transferred from the drive roller to the belt.
A typical portable conveyor for agricultural products will be mounted in a frame supported on wheels and include an actuator operative to raise and lower an upper discharge end of a conveyor tube while the lower intake end stays near the ground to receive agricultural products to be carried up the conveyor and discharged into the top of a grain bin. The lower receiving end typically includes a metal hoppered intake section where the belt runs flat before passing into the tube and moving to the troughed orientation inside the tube. In this flat portion the edges of the belt may be curved up somewhat, and there will be a seal strip, typically a stiff rubber strip, fastened along a top edge thereof to the walls of the hopper such that the lower edge thereof bears against the belt to prevent granular material from moving off the side edges of the belt.
In belt conveyors for agricultural products, there is also often a hoppered intake portion attached to the bottom end of the conveyor and extending outward generally horizontally at an angle to the tube so that the intake portion can be positioned under the center discharge of a belly dump grain trailer for example. The top run of the belt then runs horizontal to the bottom end of the tube then must make an angle upward. The belt is under tension and in response to that tension tends to rise as it turns upward from the horizontal to enter the inclined tube. In order to hold the belt down, it is common to provide an S-roller assembly whereby the belt passes from the front end of the hopper rearward over a first roller at the bottom of the tube and under a second roller that is under the first roller then up the inclined tube.
Problems commonly arise when conveying small particles such as grains, and in particular very small oily particles such as canola or flax. The seeds tend to move over the side edges of the belt, for example at the S-roller assembly and under the seal strips. The seeds gather under various portions of the belt and under the seal strip where they are crushed. The crushed oilseeds release oil which causes the belt to slip on the drive rollers, and the crushed seeds are very sticky and gummy and build up on the belt and rollers, under the seal strip, and in various other areas under and around the belt, fouling the mechanisms.
U.S. Pat. No. 8,727,108 to Dekoning addresses this problem by providing a seal over raised edges of the belt in the intake area, and a trap opening configured to allow seeds moving up the tube under the belt to fall out of the tube.